Bump-head Sunfish,
Mola alexandrini(Ranzani 1839)

A Bump-head Sunfish, Mola alexandrini, from off New South Wales. Source: Rob Harcourt. License: All rights reserved

Summary:

A grey to dark reddish-brown ocean sunfish, becoming dusky white below, with grey to dark reddish-brown fins, and many small to larger pale spots and irregular blotches on the body.

The Bump-head Sunfish (also called the Short Sunfish) was previously known as Mola ramsayi (a junior synonym). In Bali, Indonesia, Bump-head Sunfish often gather at cleaning stations to have parasites removed by Schooling Bannerfish.

Bump-head Sunfish,
Mola alexandrini(Ranzani 1839)

More Info

Distribution

In Australian waters, known from northern New South Wales, around the south to about Geographe Bay, Western Australia, including around Tasmania, off the Cobourg Peninsula, Northern Territory, and in the Lord Howe Island region.

Ocean sunfishes lack a true tail or caudal fin. Instead, they has a clavus, a rudder-like structure formed from extensions of the dorsal and anal fin rays. The clavus is broadly rounded and often has a low scalloped margin of rounded projections (called ossicles).

Colour

Grey to dark reddish-brown dorsally, becoming dusky white below, with grey to dark reddish-brown fins, and many small to larger pale spots and irregular blotches on the body.

Feeding

Once thought to be relatively inactive fishes that fed on pelagic gelatinous animals, recent research and sightings indicate that molas undertake deep-water forays to feed on colonial animals such as siphonophores.